WIRE LESS SPEED CONTROL OF AC MOTOR (USING MOBILE) ABSTRACT: The main idea of this project is to control the speed of an AC motor by wire less communication using DTMF decoder technique which is implemented by an embedded controller. In this we are using Mobile unit for wire less communication. Dual-tone multi-frequency (DTMF) signaling is used for telephone signaling over the line in the voice-frequency band to the call switching center. To meet this requirement we have designed an embedded system. The version of DTMF used for telephone tone dialing is known by the trademarked term Touch-Tone. Other multi-frequency systems are used for signaling internal to the telephone network. A machine that converts electrical power into mechanical power is called Motor. Power devices are used in speed control circuits of AC motors to get high reliable operations at large currents. Various methods are available to control the speed of the AC motor; here we control the motor speed by applying the DTMF decoder technique. In this system our mobile signals are goes to DTMF decoder. And this DTMF decoder is interfacing with the embedded controller. The controlling device controls the speed of the motor. Here there are mobile keys, which serve the purpose of increasing or decreasing the speed of the motor. This speed of the motor varies in steps according to the selection of key over the particular range. BLOCK DIAGRAM: UNDERSTANDING OF: Embedded Controller, AC Motor, LCD Module, Mobile unit DTMF decoder , Keil Compiler.